This invention relates to multibeam lens antennas, particularly for radar systems.
Basic background information may be found in the "Radar Handbook", Merrill Skolnik, Editor-in-Chief, McGraw-Hill Book Company, New York, 1970, and the references cited therein. Lens antennas are covered in section 10.9, and multibeam forming in Section 11.9.
The following items are referenced by number in he "Detailed Description" herein, and provide significant background information:
1. Walter Rotman and R. F. Turner, "Wide-Angle Microwave Lens for Line Source Applications", IEEE Transactions on Antennas and Propagation, Vol. AP-11, pp. 623-632, November 1963. PA1 2. Donald H. Archer, "Lens-Fed Multiple Beam Arrays", Electronic Progress (Raytheon Company), Vol. XVI, No. 4, pp 24-32, Winter 74. PA1 3. Wilbur H. Thies, Jr., "Omnidirectional Multibeam Antenna," U.S. Pat. No. 3,754,270, Aug. 21, 1973. PA1 4. David T. Thomas, "Multiple Beam Synthesis of Low Sidelobe Patterns in Lens Fed Arrays," IEEE Transactions on Antennas and Propagation, Vol. AP-26, pp. 883-886, November 1978.
Other U.S. Patents of interest include U.S. Pat. No. 3,359,560 to Horst which discloses a cylindrical dielectric lens comprising a mass of dielectric beads supporting an array of randomly oriented insulated metallic slivers in the interstices between the beads. U.S. Pat. No. 3,761,935 to Silbiger et al. discloses a wide-angle microwave scanning antenna array which includes an assembly of two stationary, parallel, concentric, spaced cylindrical surfaces providing a path for microwaves. U.S. Pat. No. 3,116,486 to Johnson et al. discloses a lens system in which electromagnetic waves incident on a Luneburg lens sphere are focused by the lens to a focal point on the opposite surface of the sphere. U.S. Pat. No. 3,550,139 to McFarland discloses a dielectric lens being shaped as a sector of a hemisphere and having a spherical surface of the sector being less than 180.degree. . U.S. Pat. No. 3,656,165 to Walter et al. discloses a geodesic Luneburg lens antenna which when excited by a single dual polarized feed will produce two divergent beams, one horizontally and the other vertically polarized, which has a circular lens aperture, a conical portion and a contoured portion. Excitation of the Walter et al. lens by two separate feeds at particular locations will result in the capability of providing arbitrary elliptical polarization including linear and circular polarization.